Very little is known about HIV sexual risk behaviors and other health risk behaviors such as drug use among youth in the Middle East and North Africa. The study will collect and analyze nationally representative survey data on approximately 3,000 young people age 15-24 living in the Occupied Palestinian Territories (OPT) of the West Bank, East Jerusalem, and Gaza, as well as qualitative data on a subsample of respondents. It will be the first of its kind in the region to gather representative data on both HIV-related perceptions and engagement in health risk behaviors of youth. It will use Audio Computer Assisted Self-Interview (ACASI) to obtain sensitive information on these behaviors and will employ rigorous approaches to elicit young peoples' subjective assessments of risk and their expectations about the future. The research is intended to improve our understanding of the determinants of young men's and women's attitudes toward and engagement in risk behaviors such as smoking, drug use and sexual behavior, the determinants of their mental health and expectations for the future, and the impacts of prolonged violence and economic hardship on risk-taking behavior. Knowledge of these psychological and health-behavioral responses will provide insights relevant to youth populations in many other countries and regions that have been subject to long term political or communal violent conflict. The survey will also serve as a baseline for future surveillance of youth behavior and well-being in the OPT. The specific aims of this research are: 1. Investigate the epidemiology of HIV risk behaviors, other self-destructive behaviors (smoking, substance abuse, violence), and mental health problems in a random sample of Palestinian youth. Identify subgroups of youth that are at particular HIV risk and identify 'gateway' patterns or behaviors (e.g., age at first use of tobacco or drugs) associated with later HIV and other health risks. 2. Investigate the formation of Palestinian youths' perceptions of the risks and benefits of potentially harmful behaviors and their subjective expectations about future life chances. Elucidate the relationships of exposure to violence, psychological trauma and economic hardship to young Palestinians' mental health and future orientation, and to their engagement in HIV-related and other high risk behaviors. 3. Identify risk factors and protective factors (at individual, peer, family, and community levels) for mental health problems and self-destructive behaviors, including HIV related behaviors. Explore the interaction of risk and protective factors and identify which are likely to be modifiable through interventions.